The invention relates to a heat exchanger for a convector heater and a method of heating air thereby. Convector heaters rely on conduction of heat from a heat source to a flowing air-stream. Heat sources, particularly tubular electric heating elements, are usually such that basically only local heating of the air is possible directly from the source. Metal fins may be attached to the heat source to spread the heating effect but known arrangements do not achieve a satisfactorily uniform spread of air temperature across the stream. This may be because there is a local impedance to air or for some reason the heat exchange across the stream may be uneven.
The present invention seeks to provide an improved heat exchanger.
According to the invention there is provided a heat exchanger for a convector heater comprising an elongate heat source; a spine extending around and in intimate contact with the source for transfer of heat therefrom; and a pair of banks of fins projecting from the spine, the banks being disposed in Vee formation and the individual fins within each bank all being mutually parallel.
In operation the source of heat produces heat which is conducted via the spine along the fins. The heat is then transferred to air surrounding the fins, which air rises, thereby setting up a convection flow. A low resistance to this convection flow is obtained by aligning the fins with the convection flow which is normally vertical, or at least has a substantial vertical component. For this reason the fins in both banks preferably all have their planes mutually parallel.
Normally, the heat exchanger will be used in a convector heater which comprises a cabinet enclosing the heat source at the bottom, the banks of fins projecting upwardly and laterally within the cabinet. The fins will extend in vertical parallel planes transverse to the axis of the heat source, which will normally be horizontal. The fins face each other and therefore radiate heat towards each other. Thus, radiated heat is confined largely to the fins and the heat output from the heater is imparted to the circulating air, thus minimising directly radiated heat.
Preferably the source of heat is a sheathed electric heating element, preferably of the kind having a heater wire enclosed in metal oxide powder sheathed in a metal jacket. However, it is envisaged that the heat source may, for example, be a hot-water pipe.